Manually activated pre-filled syringe cartridges are commercially available from a variety of manufacturers, including the owner and assignee of the present invention. Pre-filled syringe cartridges are used in the administration of drug solutions, drug suspensions, vaccines, medicinal therapies, and any other liquid medicament by parenteral injection.
As such, pre-filled syringe cartridges include a primary drug chamber, a hypodermic needle permanently affixed to and in fluid communication with the drug chamber, and a piston slidably received in the drug chamber. The pistons of the pre-filled syringe cartridges often include a plunger subassembly, which may include a plunger inner and a plunger outer, to force the liquid medicament from the needle. Pre-filled syringes are typically prepared by pharmaceutical companies or sterile filling contractors in a sterile filling room in which the drug and the syringe are brought together in a sterile manufacturing environment wherein all components and drug solutions are isolated from microbial contamination.
The practice of sharing syringes without adequate sterilization between successive users is a major contributor to the transfer of Human Immunodeficiency Virus (HIV) and Hepatitis with subsequent severe repercussions for the sufferer and at a high cost to society for supporting and providing medical attention to sufferers.
Furthermore, health professionals may be exposed to used syringes, which can lead to inadvertent needlestick injuries and possible exposure to infective pathogens or other contaminants. In response to this problem, retractable syringes have been developed with the aim of preventing syringe re-use and/or needlestick injury by used syringes.
In developing such retractable syringes, relatively complicated retractable needle assemblies have been devised which often are developed for a particular syringe barrel shape or configuration and cannot be readily mounted to a syringe barrel having a different shape or configuration. This is particularly a problem with glass syringe barrels, which are generally in short supply, many of which glass barrels do not have a desired shape or configuration for mounting a retractable needle subassembly. Accordingly, many existing safety syringes require specifically-tailored retraction mechanisms and barrel configurations, which may require complex manufacturing processes or operational changes. The materials employed in the manufacture of such safety syringes must meet complex criteria for regulatory approval. Additionally, safety syringes must remain aesthetically-similar to conventional syringes to facilitate broad adoption and must be easy-to-use for self-administering patients.